Here's a cute little newly announced feature of 3.0 - Find My iPhone. Users who have the 3.0 firmware and MobileMe will be able to log in to MobileMe, see a map with their iPhone's physical location, and send a message to the iPhone instructing whoever has it to call a number.

And you can use a Remote Wipe feature to erase all data on your iPhone, and restore it to factory settings. Here's hoping Apple never decides to take over the world....